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  2. Hierarchical database model - Wikipedia

    en.wikipedia.org/wiki/Hierarchical_database_model

    A hierarchical database model is a data model in which the data are organized into a tree-like structure. The data are stored as records which are connected to one another through links. A record is a collection of fields, with each field containing only one value. The type of a record defines which fields the record contains.

  3. Extract, transform, load - Wikipedia

    en.wikipedia.org/wiki/Extract,_transform,_load

    A new dimension row is added with the new state of the source system; a new surrogate key is assigned; source key is no longer unique in the lookup table Fully logged A new dimension row is added with the new state of the source system, while the previous dimension row is updated to reflect it is no longer active and time of deactivation.

  4. Table (database) - Wikipedia

    en.wikipedia.org/wiki/Table_(database)

    In a database, a table is a collection of related data organized in table format; consisting of columns and rows. In relational databases , and flat file databases , a table is a set of data elements (values) using a model of vertical columns (identifiable by name) and horizontal rows , the cell being the unit where a row and column intersect ...

  5. Relational model - Wikipedia

    en.wikipedia.org/wiki/Relational_model

    A table is specified as a list of column definitions, each of which specifies a unique column name and the type of the values that are permitted for that column. An attribute value is the entry in a specific column and row. A database relvar (relation variable) is commonly known as a base table.

  6. Microsoft Power BI - Wikipedia

    en.wikipedia.org/wiki/Microsoft_Power_BI

    The first release of Power BI was based on the Microsoft Excel-based add-ins: Power Query, Power Pivot and Power View. With time, Microsoft also added many additional features like question and answers, enterprise-level data connectivity, and security options via Power BI Gateways. [10] Power BI was first released to the general public on 24 ...

  7. Entity–attribute–value model - Wikipedia

    en.wikipedia.org/wiki/Entity–attribute–value...

    Columns with an atomic data type (e.g., numeric, varchar or datetime columns) can be designated as sparse simply by including the word SPARSE in the column definition of the CREATE TABLE statement. Sparse columns optimize the storage of NULL values (which now take up no space at all) and are useful when the majority records in a table will have ...

  8. Help:Table - Wikipedia

    en.wikipedia.org/wiki/Help:Table

    A table is an arrangement of columns and rows that organizes and positions data or images. Tables can be created on Wikipedia pages using special wikitext syntax, and many different styles and tricks can be used to customise them. Tables can be used as formatting instrument, but consider using a multi column list instead.

  9. Join (SQL) - Wikipedia

    en.wikipedia.org/wiki/Join_(SQL)

    The danger comes from inadvertently adding a new column, named the same as another column in the other table. An existing natural join might then "naturally" use the new column for comparisons, making comparisons/matches using different criteria (from different columns) than before. Thus an existing query could produce different results, even ...